#!/usr/bin/perl -w
use strict;

my $secret_number; 
my $total_guesses; 

sub init_game
{
   $secret_number = int(rand 101);
   $total_guesses =0;
}  

init_game();  #initial start of game parameters

print "General Rules:\n";
print "  I have a secret number from 0-100\n";
print "  Your job is to guess this number!\n";
print "  You will be given hints for each guess\n";
print "  Enter quit if you give up!\n";

while ( (print "Enter a guess: "), 
        (my $number = <STDIN>) !~ /^\s*q(uit)?\s*$/i  
      )
{
    next if $number !~ /\S/;   #skip blank lines
    $number =~ s/^\s*//;       #no leading spaces
    $number =~ s/\s*$//;       #no trailing spaces (also chomps)
    
    if ($number =~ /[-.]+/)
    {
       print "only unsigned integers are allowed!\n";
       next;
    }

    if ($number =~ /\D/)
    {
       print "Invalid!! Only integer numbers >=0 are allowed!\n";
       next;
    }
    
    if ($number >100)
    {
       print "Hey, you didn't pay attention, max number is 100!\n";
       next;
    }
    
    if (game_finished($number))
    {
        print "would you like to play again?:(Y|y|yes)\n";
 
        if ( (my $answer =<STDIN>) =~ /^\s*Y(es)?\s*$/i)
        {
           init_game();
           print "New Game Starting!!!\n\n";
        }
        else
        {
          exit(0);
        }
    }   
}

sub game_finished
{
    my $number = shift;
    $total_guesses++;
    
    if ($number == $secret_number)
    {
       print "Horray! you got the secret number, $secret_number!\n";
       print "But it took you $total_guesses total guesses to do it!!\n";
       return(1);
    }
    
    if ($number < $secret_number)
    {
       print "You guessed too low! Dummy!\n";
       return(0);
    }
    
    if ($number > $secret_number)
    {
       print "You guessed too high! Duh!\n";
       return(0);
    }
}
Example Session:

General Rules:
  I have a secret number from 0-100
  Your job is to guess this number!
  You will be given hints for each guess
  Enter quit if you give up!
Enter a guess: 50
You guessed too high! Duh!
Enter a guess: 25
You guessed too high! Duh!
Enter a guess: 12
You guessed too high! Duh!
Enter a guess: 6
You guessed too low! Dummy!
Enter a guess: 8
You guessed too high! Duh!
Enter a guess: 7
Horray! you got the secret number, 7!
But it took you 6 total guesses to do it!!
would you like to play again?:(Y|y|yes)
y
New Game Starting!!!

Enter a guess: q